The HA-2's power amplification circuit for the headphones is Class AB built with integrated circuits (ICs) and discrete transistors. The discrete transistor output stage uses hand-picked and matched parts. The output transistors are biased to operate in their most linear range for the critical small signal, and deliver their full potential when power is required.

Made for iPod®, iPhone® and iPad®

The HA-2 passes Apple's "MFi" certification and is compatible with the latest iPod, iPhone and iPad to be used as the digital audio output accessory of these devices. By tapping directly into the digital audio signal of these devices and converting the audio to analogue using the high performance SABRE32 Reference DAC, music from your favorite portable device will sound its best. Furthermore, for users with high-resolution music playback apps, the HA-2 does not require the use of a Camera Connection Kit (CCK). The data cables that come with your Apple device or the supplied Lightning cable is sufficient.

Compatible with Android

The HA-2’s micro-USB input port works with Android devices that support USB OTG (USB On-The-Go) and USB Audio Class. A special USB OTG cable is supplied with the HA-2 to facilitate the connection. When used with a compatible Android device, the HA-2 can support the device's built-in music app, tones and notifications. Additionally, a high-resolution music playback app can use the HA-2 as its external DAC to play lossless PCM and DSD audio files.

Audio-In and Line-Out

The HA-2 has a 3.5 mm Audio-In port to support portable music players that do not have a USB-compatible digital output. While the HA-2 is used with one of its USB digital input ports, the 3.5 mm jack acts as Line-Out for the USB DAC.

ESS Sabre32 Reference DAC

The DAC is one of the most important components for digital audio playback. The ES9018-K2M DAC chip used in the HA-2 is the mobile version of the ES9018S used in our award-winning HA-1 desktop headphone amplifier. With the ESS patented 32-bit Hyperstream™ DAC architecture and Time Domain Jitter Eliminator, the SABRE32Reference DAC delivers an unprecedented performance for mobile applications. To learn more about the technologies behind the exceptional performance of the SABRE DAC, please read the SABRE Technical White Paper

Asynchronous USB DAC

By bypassing the smartphone's built-in DAC and headphone amplification circuit that are often cost-constrained, the HA-2 turns a smartphone into a high performance digital audio player. The asynchronous USB DAC input of the HA-2 also works with PC and Mac computers to replace the built-in sound card and support high-resolution audio playback with PCM up to 384 kHz 24-bit and DSD up to 12 MHz (DSD256).

Clean Signal Path

There is no DSP (Digital Signal Processor) in the HA-2. Volume control is operated by a combination of the DAC chip's internal digital volume control and an analog potentiometer (the familiar volume knob). Bass boost is performed by pure analogue audio circuits. By avoiding re-digitising the audio signal for volume adjustment or bass boost, the HA-1 provides a clean signal path for the audio.

Bass Boost

For those who like a bit more punch and impact with their music, the HA-2 offers a Bass Boost function. With Bass Boost off, the HA-2 delivers a ruler-flat frequency response; with Bass Boost on, the HA-2 adds force and impact to the sub-bass region without muddling the important mid- to high-frequency bands.

Two Gain Settings

The HA-2 offers two gain level settings for optimal headphone matching. The High Gain mode is capable of driving large power-hungry headphones, delivering up to 300 mw into 16-Ohm headphones. The Low Gain mode is intended for sensitive In-Ear Monitor type earphones.

Rapid Charging

The HA-2 features patented VOOC rapid charging technology from OPPO. Using the supplied rapid charger, the internal battery can be quickly and safely charged to 75% capacity in about 30 minutes. It only takes approximately 90 minutes to fully charge the battery. A quick charge gives the HA-2 hours of operation time.

Mobile Power Bank

The HA-2 functions as an external battery pack to charge your mobile device. Utility and convenience are factors we wanted to address with the HA-2, so you can ditch the bulky spare battery pack and carry just the HA-2 with you mobile phone.

Build Quality

The HA-2 is housed in an aluminum chassis wrapped in genuine leather. The beveled metal edges and contrast stitching on the leather are eye-catching. Its fit and finish will instill a sense of pride when using the product. The HA-2 meshes equally well in the pocket of an urban Millennial or on the desk of a business executive.